Internal-combustion engine piston lubrication



'Oct 9, 1951 H. s. BENJAMIN ET AL 2,570,424

INTERNAL-COMBUSTION ENGINE PISTON LUBRICATION Filed Aug. 31, 1948 Cttornegs Patented Oct. 9, 1951 UNITED STATES PATENT oFFlcE INTERNAL-COMBUSTION ENGINE PISTON LUBRICATION Harry S. Benjamin, Detroit, and Hallison R. De Harte, Farmington, Mich., assignors to The Leading Engine Company, Farmington, Mich., a corporation of Michigan Application August 31, 1948, Serial No. 47,038

2 Claims.

This invention relates to internal combustion engines.

jT/he object of this invention is to provide an internal combustion engine wherein the piston is lubricated, according to the conditions of use,

by providing the cylinder with a skirt which extends downward into the crankcase and has holes splashed and sizes of the holes as adjusted by a lubricant regulator encircling the cylinder skirt determining the amount of lubricant reaching the piston, an engine which is used in a hot climate or under severe load conditions requiring more lubricant than an engine used for light duty'or .in a cool climate.

In the drawings:

Figure 1 is a centra1 longitudinal section, partly in side elevation,v through an internal combustion engine according to apreferred form of the invention; and

Figure 2 is a -top plan view of the right-hand portion of the engine shown in Figure 1.

1 Referring to the drawings in detail, Figure 1 shows, in longitudinal section, an internal combustion engine, generally designated I0, accord- -ing to a preferred form of the invention. The

engine I3 includes a crankcase II, to which a reduction gear box generally designated I2 is adjustably secured, as described below,` and constituting one aspect of the invention. The crankcase I'I is of hollow tank-like or box-like'form with an inwardly-projecting bearing boss I3 on usual bearing cap 24 of semi-circular form bolted thereto as at 25. The bearing bosses I3 and I1 are recessed as at 26 and 21 respectively to receive oil seals 28 and lubricant passages 30 and 3| are provided for conducting lubricant to and from the crankshaft 20. Mounted on the crankshaft 20 is e, gear 32 which drives the cam shaft,

the latter in turn operating the engine valves (not shown). The cam Iand valve mechanism are conventional and their details form no part of the present invention.

Y, The bottom of the crankcase II is approxi- (not shown).

mately concentric with the axis of the crankshaft 20. In this manner, the crankshaft 20 is provided with a supply of oil regardless of whether the engine is tilted or is level. In order to lubricate the crank pin bearing 22, a scoop 34 mounted on the `bearing cap 24 to throw the lubricant around by the splash system is used. The lower end of the chamber 33 is bored and threaded to receive a screw plug 35, and a mounting ilange 36 is provided at the bottom thereof for mounting the engine I0 upon any suitable apparatus which it is to drive, for example, a power lawnmower, a motor-scooter, portable generator, portable pump or handy-billy.

The top of the crankcase I I immediately above the crank portion 31 of the crankshaft 20 is provided with an aperture 3B into which a downwardly projecting skirt 39 of the engine cylinder 40 is secured, as by the bolts 4I which also pass through the cylinder head 42 and secure'it and the cylinder 40' to the crankcase II. The bolts 4I are threaded into threaded bores -43'in the top of the crankcase II. The cylinder 40 is provided with heat-radiating and air-cooling iins 44 and the cylinder head 42 is similarly provided with fins 45. A spark plug 46 threaded through an aperture (not shown) in the top of the cylinder head 42 ignites the charge composed of a mixture of gasoline and air.y The spark plug 46 is connected to a conventional ignition system The incoming and outgoing gases are admitted and discharged through ports 41 and 48 to which are bolted the usual intake and exhaust manifolds (not shown) The cylinder 40`and its skirt 39 are bored as at 49 to receive a cylinder `liner5il which in turn has a bore 5I receiving a piston 52. The latter is provided with a wrist pin 53 which passes through the wrist pin bearing 54 on the upper end of the connecting rod 23. The piston 52 is provided with piston rings 55 snugly engaging the bore 5I. The liner 5I) is preferablyY pressed into the bore 49 'and secured therein by a press t. In order to sleeve 59 is then clamped in its adjusted position by the set screw 6I, access to which is obtained by a threaded plug 62 mounted in a threaded crankshaft opening 63.

The rearward end wall of the crankcase I I adjacent .the inwardly projecting boss I3 is flattened to receive the correspondingly flattened surface of the face plate |2a of the reductio-n gear box I2. The crankcase II and face plate |20, are drilled and threaded at intervals on equal radii to receive bolts 64 which are equidistant from the axis of the crankshaft 20. By this means, the face plate I2a may be swung to different positions and rebolted by reinserting the bolts 64 so as to differently position the gearbox I2 relatively to the axis of the crankshaft and thereby adapt the engine to being mounted on different machines requiring different output shaft positions.

The reduction gear box I2 is vbored centrally to provide a bearing bore 65 therein. Bolted as at 96 to ,the annular rim of the housing portion of the reduction gear box I2 is the correspondingly annular rim of the housing end plate 61 of the gearbox I2. The end plate 61 is roughly conical in shape and has an inwardly-extending bearing boss -69 provided with a bore 'I0 co-axial with the bore E5.

Thev crankshaft 20 at its rearward end is provided with a reduced diameter portion '|I (Figure 1) and the annular shoulder 'I2 therebetween is provided with notches 13. The notches 'I3 serve to. receive correspondingly shaped tongues 'I4 which project axially from a tubular shaft 15 journaled in the bearing bore 16 of the neck portion 6I and .carrying a pinion 'I'I at its outer end. The reduced diameter Vportion .'II of the crank- .shaft 20 is provided with a keyway or spline I8 for the reception of a pulley, sprocket, or the like `when a. direct drive is desired, with the reduction gearbox |.2 completely removed. This type of drive, for example, is used in motor scooters.

The hollow shaft 'I5 and its pinion '|1 are provided with a bore 19 into which the reduced diameter crankshaft portion '|I smoothly fits.

Meshing with the pinion TI is an internal ring gear the hub 8| of which is keyed as at 82 to the central portion 83 of a reduction gearbox output shaft 84 having a reduced diameter portion 85 which is provided with a keyway or spline B6 for receiving a sprocket, pulley, coupling or the like. The centralportion 83 of the output shaft 84 is j ournaledin the bearing bore 'l0 of the bearing boss 69 (Figure 1) lwhereas the reduced diameter inner endy portion 81 is journaled in the bore 95 of the. bearing boss S4. By this construction, the reduction` gear box I2 is made completely removable by removing the bolts 64 and withdrawing the tubular shaft 'I5 from over the reduced diameter portion 1I of the crankshaft 20, at the same time withdrawing the tongues 14 from the notches 'I3 by which a driving connection is established between the tubular shaft 15 and the crankshaftA 20. As previously explained, the face plate. 59 can be rotated while the bolts 64 are removed, relocating the gearbox in another position, such as the chain line position shown in Figure 4.

The engine I0 is provided with a conventional carburetor which has been omitted to simplify the showing, and this is supplied with fuel through piping (not shown) leading to a fuel tank of cylindrical form which rests in a cradle 9| having arcuate supporting portions 92 extending forwardly from bracket portions 93. The latter are VAprovidleclwith ears 94` which are bolted down by 4 two of the cylinder head bolts 4|. In order-to hold the tank 99 in the cradle 9|, there are provided two retaining bands or straps 95 secured as at 99 and 91 to the rearward and forward sides respectively of the cradle 9|. The bands 95 are interconnected by a bridge portion 96a (Figure 2). The cradle 9| is also provided with forwardly and downwardly extending portions 98 terminating in offset tongues 99 and having arcuate lower surfaces |00 which are continuous with and form a part of the lower surfaces of the arcuate portions 92 (Figure l).

Fitting upwardly beneath the arcuate surfaces |90 is a correspondingly arcuate top portion |0| (Figure 1) of a fan housing |02 having spaced slots If0'3 for receiving the offset tongues 99. The fan housing |02 is secured -by the screws |05 to drilled and threaded bosses |05 distributed at intervals around the periphery of the end plate I5. The fan housing |92 is provided with a central apertureY or fan air intake opening |01 through which air is drawn inward by the fan blades |08 mounted on the front wall of a cup-shaped-ywheel |09, the rearward rim portion I |0 of which Yis provided Vwith an annular recess or stepped portion I II located immediately adjacent a correspondingly stepped portion I I2 inside the flange I6 (Figure l). The portions III and I I 2 enclose annular space receiving a sealing ring ||3 whereby the joint between the rim portion I|0' and the flange I6 is effectively sealed against the entrance of moisture, dust, or any other undesired foreign matter which may be drawn into the fan housing |02 through the opening |01. The air vthus drawn in is discharged through an opening ||4 in the rearward upward portion of the fan housing |02, so located as to discharge this cool air directly upon the cooling fins 44 and 45 of the cylinder 40 and cylinder head 42.

The hollow cup-shaped flywheel |09 is provided with an approximately cylindrical inner chamber H5 which is adapted to receive a conventional magneto indicated diagrammatically at II6 and having its rotor keyed or otherwise secured as at I I'| to the forward reduced diameter portion II8 of the crankshaft 20. The latter in turn has a tapered portion lI I9 which is seated in va correspondingly tapered bore |29 in the hub |2I of the flywheel |09. The tapered portion I I9 terminates in a keyed or splined reduced diameter portion |22 upon which is mounted a starting pulley 23 having oblique notches (not shown) which serve to receive the knotted end of a starting cableV (not shown) wound on the pulley |23 for starting purposes. The outer end of the'reduced diameter crankshaft portion |22 is threaded to receive a nut |25 (Figure 1) by which the pulley |23 is held in assembly on the crankshaft 20.

Prior1 to the operation of the engine I0, the reduction gearbox I2 is mounted in the most convenient location in the manner described in connection with the construction thereof, so that the output shaft portion 85 occupies the desired position. Let it be assumed that fuel is supplied to the tank 90 and high tension electricity to the spark plug 46 so that gasoline flows into the carburetor andV is there mixed with the air to provide an explosive charge. The operator then winnds the starting cable around the starting pulley |23 and by a pull on the cable rotates lthe pulley |23 and crankshaft 2.0. This action also spins the flywheel |09 and therrotor of the magneto IIS, causing high-tension electricity to flow through the ignition system to the sparkplug 46,

igniting the explosive charge without the cylinder bor 5|.

The ignition of the explosive charge causes an explosion which drives the piston 52 downward, rotating the crankshaft 20. As sparks are caused to jump in timed relationship across the electrodes of the sparkplug 46 and the valves (not shown) are likewise operated in timed relationship by the camshaft from the pinion 32, the crankshaft 20 is rotated continuously as long as fuel is supplied to the motor from the tank 90.

Meanwhile, the rotation of the flywheel |09 causes air to be vdrawn in through the air intake opening |01 by the fan blades |08 and discharged through the opening ||4 over the cooling fins 4| and 45, cooling the cylinder 60 and cylinder head 42. The skirt 39 of the cylinder 40 is also cooled by oil splashed up by means of the scoop 34 from the sump 33 against it, and a portion of the oil passes through the holes 56, 51 into the lower end of the cylinder liner bore 5|, to lubricate the piston 52. The holes 56, 51 are placed in number and location according to the kind of service and climate in which the engine is intended to operate. For a hot climate and very heavy duty, the holes 56, 51 are frequently spaced so as to provide a maximum of lubrication. For a cooler climate or light duty, the .number of the holes or their diameters, or both, are correspondingly reduced. Regulation of the quantity of oil entering the holes 56, 51 is also obtained by adjusting the sleeve 59 to leave these holes completely open or partially close them.

After the engine has been in use for some time, the piston rings 55 become worn or lose their tension. As a result of this, oil is by-passed to the top of the piston and causes fouling of the spark plug and excess carbon around the exhaust valve. Ordinarily, new piston rings are installed to cure this condition. This expense can be eliminated or at least deferred for a while by adjusting the sleeve 59 to close the free aperture existing between the holes 60 and the holes 56, 51, thus reducing the amount of oil entering the cylinder, which amount would otherwise be in excess of that required for lubricating the cylinder walls. In this way, the pumping of oil would be reduced for the time being by cutting down the excess oil which would otherwise be pumped. The same adjustment also permits the engine to be adapted to widely varying running conditions, such as in the cold far north, on the one hand, and in hot deserts, on the other.

If at any time the flywheel |09 or magneto ||6 requires servicing, the fan housing |02 may be easily removed by removing the screws |05 and tilting the housing |02, pressing it inward adjacent the tongues 99 and swinging it outward at ,the bottom so that the aperture |01 passes over the pulley |23. This can be done without disturbing any of the fuel or ignition lines, as is necessitated in similar work on prior engines.

What we claim is:

l. In an internal combustion engine, a crankcase, a chankshaft journaled in said crankcase, a cylinder mounted on said crankcase and having a skirt projecting into said crankcase, a piston reciprocably mounted in said cylinder and drivingly connected to said crankshaft, said skirt having lubricant passages therethrough, a lubricant regulator movably mounted on said skirt and having lubricant passages alignable with said skirt lubricant passages, and a lubricant distributor operatively connected to said crankshaft and arranged to direct lubricant against said skirt and into said passages.

2. In an internal combustion engine, a crankcase, a crankshaft journaled in said crankcase, a cylinder mounted on said crankcase and having a skirt, projecting into said crankcase, a piston reciprocably mounted in said cylinder and drivingly connected to said crankshaft, said skirt having lubricant passages therethrough, a lubricant regulator comprising an annular band movably mounted on said skirt and having lubricant passages alignable with said skirt lubricant passages, and a lubricant distributor operatively connected to said crankshaft and arrangedY to direct lubricant against said skirt and into said passages.

HARRY S. BENJAMIN. HALLISON R. DE HARTE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,071,781 Nelson Sept. 2, 1913 1,151,732 Steedman Aug. 31, 1915 1,167,970 Balz Jan. 11, 1916 1,364,102 Forkner Jan. 4, 1921 1,552,572 Scannell Sept. 8, 1925 1,591,346 Tushaus July 6, 1926 1,622,687 Szekely Mar. 29, 1927 2,250,809 Martin et al July 29, 1941 2,256,601 West Sept. 23, 1941 FOREIGN PATENTS Number Country Date 492,407 France Mar. 18, 1919 269,938 Great Britain Apr. 25, 1927 652,509 Germany Nov. 2, 1937 

